In power conversion applications, an interleaved multi-phase power supply is widely used in large power and large current condition since the interleaved multi-phase power supply may be able to provide a large output current with small current ripples, and optimized thermal and power distributions. However, due to biases of the load characteristics and of the control parameters are existed among multiple phase circuits of the interleaved multi-phase power supply, output current biases may thus be generated among multiple output current signals corresponding to the multiple phase circuits. The output current biases may affect efficiency and stability of the system. Therefore, current sharing control is indispensable in the interleaved multi-phase power supply. Generally, the interleaved multi-phase power supply may include a plurality of identical DC-DC converter ICs, and each DC-DC converter IC is used to control the corresponding phase circuit of the interleaved multi-phase power supply. For a prior current sharing control, each DC-DC converter IC may comprise a pin COMP. One DC-DC converter IC is operated as a master IC, and the remained DC-DC converter ICs are operated as slave ICs. The master IC receives a feedback voltage signal representative of an output voltage signal of the interleaved multi-phase power supply, and further compares the feedback voltage signal with a reference voltage signal to generate an error signal which can be drawn out of the master IC through the pin COMP. Each slave IC receives the error signal from its pin COMP. Due to the master IC and the slave ICs adopt the same error signal as a reference value of their output current signals, the current sharing control of the multiple output current signals can be realized.
However, for a DC-DC converter IC having low quiescent current, parasitic capacitor on the pin COMP may affect stability and dynamic response of DC-DC converter IC. Thus, the current sharing control is unable to be realized by adopting the pin COMP.
Therefore, it is desired to have a solution for realizing the current sharing in the interleaved multi-phase power supply with a plurality of the DC-DC converter ICs having low quiescent current.